Knob



FIG. 1 is a perspective view of a knob of the present claimed design;

FIG. 2 is a side view of the knob shown in FIG. 1, each side view being identical thereto;

FIG. 3 is a front view of the knob shown in FIG. 1; and,

FIG. 4 is a rear view of the knob shown in FIG. 1.

Features shown in broken lines in the drawings form no part of the claimed design. 

I claim the ornamental design for a knob, as shown and described. 